The invention generally relates to a digital signal processing apparatus adapted to measure the ratio of two or more digital signals. More particularly, the invention relates to a signal ratio measuring apparatus adapted to accurately monitor two or more high frequency digital signals, which are represented in terms of a relative ratio of the frequencies thereof for process control operations.
In many applications and environments, the relationship between various operating parameters of a process may be used to maximize the efficiency and cost effectiveness of the process. For example, a manufacturing process may include a variety of intermediate operations, the interaction of which results in the success of the entire process. The interaction between intermediate operations in a manufacturing or other process may be monitored by the relative operational characteristics between such intermediate operations. The information relating to such intermediate operations of the process may be represented in ratio form for ease of interpretation and analysis of process parameters.
Presently, for example, the operation of mechanical devices, such as motors, used in various manufacturing processes, may be analyzed by means of integrated monitoring devices, diagnostic equipment or the like. For example, a motors speed of operation may be monitored by a tachometer to determine whether the motor is operating within a desired operating range. Devices such as tachometers are commonly used in industrial manufacturing to measure the speed of operation of motor driven equipment within a process. This as well as other types of equipment measure the performance of independent portions of a system, and therefore do not provide any information regarding the interaction between these independent operations within a manufacturing process. Information regarding the interaction of various intermediate processes would allow enhanced process control and quality control functions to be achieved. Similarly, other processes besides industrial or manufacturing based, may also be enhanced with information regarding the interaction of intermediate operations within the overall process.
There are known digital based decoding apparatus which are designed to process two or more data streams transmitted through separate data channels in a synchronized manner. Such decoding apparatus are quite complicated and costly, and do not provide a relative indication of process parameters, represented as a ratio. Other known apparatus are designed to produce signals which vary as the ratio of the frequency of a first signal stream to a second signal stream. Such a system was used to generate a feedback signal for noise reduction in the recording of frequency modulated signals. Such an apparatus is not usable to determine the relative operational characteristics between speed and time based systems within a process, represented as a ratio.